Sweeping machine with electrical drive

ABSTRACT

A hand-operated sweeping machine having two circular brooms mounted in the front area, a motor drive which rotates the circular brooms, a drive mechanism which transfers a driving force derived from the forward motion of the sweeping machine to drive the circular brooms when the motor drive is not operating, and an interrupting mechanism which automatically interrupts a connection between the motor drive and the driving mechanism when the motor drive can rotate the circular brooms faster than the driving mechanism. When the motor drive of the sweeping machine is inoperative, as when there is no electricity available to operate an electric motor drive, the sweeping machine may be operated by the driving mechanism driving the circular brooms. The interrupting mechanism automatically prevents the motor drive when operating from transferring driving force to the driving mechanism and thereby undesirably driving forward motion of the sweeping machine.

[0001] This application claims the priority of German application no.103 09 991.3, filed Feb. 28, 2003, the disclosure of which is expresslyincorporated by reference herein.

BACKGROUND AND SUMMARY OF THE INVENTION

[0002] This invention relates to a hand-operated sweeping machine withtwo circular brooms that are mounted in the front area and are equippedwith a motor drive, driving them to rotate in opposite directions.

[0003] A sweeping machine equipped with a driving means is known fromGerman Patent DE 19617986 A1. The drive of the circular brooms isimplemented by driving means which transmit the driving forces derivedfrom the forward motion to the circular brooms. As an alternative, it isstated in the publication cited above that the circular brooms may alsobe driven by an electric motor drive. An electric motor drive has theadvantage that the circular brooms will rotate at an adequate speed evenif the sweeping machine only transverses slowly or is stopped to sweepout a corner or the like.

[0004] In practice, a battery must be provided for an electric motordrive within a sweeping machine because the sweeping paths, inparticular in the case of exterior installations, are usually too longto allow a power supply by way of a cable. In the case ofbattery-powered operation, the problem may occur whereby the charge ofthe battery drops so much during sweeping a job that sweeping operationis no longer possible, for example, if the battery has not been chargedfor a sufficiently long period of time. To be able to continue thesweeping operation, the user must either replace the battery or connectthe sweeping machine to a charging unit and wait until the battery ischarged again.

[0005] An object of this invention is to permit use of a sweepingmachine equipped with a motor drive even when the motor drive is notfunctioning.

[0006] This object is achieved by the fact that in addition to the motordrive for the circular brooms, driving means which transmit the drivingforces derived from the forward motion to the circular brooms areprovided and means for automatic interruption of a connection areprovided between the motor drive and the driving means.

[0007] This design makes it possible to continue to use thehand-operated sweeping machine even when the motor drive is not inoperation, e.g., because there is no power supply, i.e., the batterycharge is too low or the available cable length has been exceeded. Inthese cases, the sweeping machine can be used for manual operation sothat the circular brooms can be driven by the forward motion. The meansfor automatic interruption of the connection between the motor drive andthe other driving means ensure that the motor drive is functional evenwhen the sweeping machine is stopped or is moving forward very slowly.The motor drive does not have a retroactive effect back on the otherdriving means and therefore does not cause any unwanted forward motionof the sweeping machine.

[0008] In one embodiment of this invention, a separate motor drive andseparate driving means are provided for each circular broom. Thisfacilitates turning corners and executing pivoting movements of thesweeping machine.

[0009] In another embodiment of this invention, an overriding couplingwhich allows the circular broom to run ahead with respect to the drivingmeans is situated between the driving means, which transmit the drivingforces derived from the forward motion, and the circular broom. In thisembodiment, the drive which is running at a faster speed transmitsdriving forces to the circular brooms. This is usually the motor drive,but it is also possible for the user to drive the circular brooms toexecute a faster rotation than that induced by the motor driving means,i.e., by moving the sweeping machine especially rapidly.

[0010] In another embodiment of this invention, an overriding couplingis provided between the circular brooms and their motor drive, allowingthe circular broom to run ahead. This achieves the result that when themotor drive is unable to function because of lack of a power supply ordue to some other defect, the circular brooms and the drives which arethen effective need not drag the motor drive.

[0011] In another embodiment of this invention, a sweeping rolleraligned across the direction of motion is provided, this roller beingequipped with a motor drive and driving means being provided so thatdriving forces derived from the forward motion can be transferred to thesweeping roller; in addition, means are also provided for automaticinterruption of a drive connection between the driving means and themotor drive of the sweeping roller. If the sweeping roller is motordriven, the sweeping function can still be maintained even when thesweeping machine is moving very slowly or even at a standstill. Hereagain, there is the problem that the motor drive may not be functionalbecause the battery is too low or there is a lack of power supply orbecause of a defect. In this case, the driving means then drive thesweeping rollers which derive driving forces from the forward motion andtransmit them to the sweeping roller.

[0012] Other objects, advantages and novel features of the presentinvention will become apparent from the following detailed descriptionof the invention when considered in conjunction with the accompanyingdrawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 shows a vertical section through a circular broom of ahand-operated sweeping machine in accordance with an embodiment of thepresent invention, and

[0014]FIG. 2 shows a schematic diagram of a drive of a sweeping rollerof a hand-operated sweeping machine in accordance with anotherembodiment of the present invention.

DETAILED DESCRIPTION OF THE DRAWINGS

[0015] The circular broom 10 shown in FIG. 1 is one of two circularbrooms mounted in the front area of a hand-operated sweeping machine.The sweeping machine is designed essentially according to the sweepingmachine known from German Patent DE 19617986 A1. This sweeping machinehas two circular brooms mounted in the front area, rotating in oppositedirections about approximately vertical axes of rotation that arepreferably inclined slightly forward. The circular brooms sweep directlytoward the center and toward the rear into the sweeping machine. Thedirt is preferably swept toward the rear into the housing through asweeper plate and is picked up there by a sweeping roller before beingsent onto a collecting container. In this embodiment, each circularbroom 10 is equipped with its own drive as illustrated on the basis ofFIG. 1.

[0016] The circular broom 10 has a base body 11, which is designed as aninjection molded plastic part. This base body 11 is essentially potshaped. A ring of bristles 13 is embedded in the edge 12 of thepot-shaped base body 11 which is open toward the bottom. The circularbroom rotates about an essentially vertical axis of rotation 14, whichis preferably inclined slightly forward in the direction of travel ofthe sweeping machine.

[0017] The axis of rotation 14 consists of a journal 15 on which ismounted a drive element 16 that is manufactured as an injection moldedplastic part. The drive element 16 has teeth 17 in its lower area whichengage with a screw 18. The screw 18 is in a rotationally fixedconnection with a roller 19 mounted on a journal 20. The journal 20 ispart of an offset axle 21 which is rotatable about the axis of rotation14 in the journal 20. The roller 19 is thus a following roller which isset behind the axis of rotation 14 with respect to the direction oftravel. The roller 19 thus always drives the drive element 16 in thesame direction.

[0018] The base body 11 of the circular broom 10 is rotatably mounted onthe drive element 16. Between the drive element 16 and the base body 11is arranged a free-wheeling coupling 22, preferably a so-calledfree-wheeling roller. This free-wheeling coupling 22 is designed so thatthe base body 11 of the circular broom 10 can run ahead in the directionof driving the driving element 16 but rotation in reverse is blocked.The same function is also achieved when a free-wheeling coupling isprovided between the worm gear 18 and the roller 19.

[0019] The base body 11 is provided with a screw wheel 23 which engageswith a screw 24 of an electric motor 25. The electric motor 25 drivesthe screw wheel 23 and thus drives the base body 11 of the circularbroom 10 in the same direction of rotation in which the circular broom10 is also driven by the drive element 16.

[0020] When the electric motor 25 is turned on, it drives the circularbroom 10 to rotate, even if the roller 19 is stopped. The free-wheelingcoupling 22 allows the circular broom to run ahead of the drive element16. If the electric motor 25 is not running, e.g., because the batteryhas discharged or because no electric power supply is possible orbecause the motor 25 is defective, then the circular broom 10 is drivenby the roller 19, the worm gear 18 and the drive element 16, 17. It isthus possible to continue operating the sweeping machine even when thereis no electric power supply and for example a sweeping job that has beenstarted can be completed.

[0021] In order not to drag on the electric motor 25 via the rollers 19when there is no power supply or when there is a defect in the electricmotor, an overriding coupling 27 is provided between the circular broom10, i.e., the base body 11 of the circular broom 10 and the electricmotor 25, this coupling preferably being designed as a free-wheelingroller. This overriding coupling is designed so that the circular broom10 can rotate at a higher rotational speed than that set by the motor25. This yields the result that if the electric motor 25 fails, it neednot be dragged along too. In addition, it is also possible to move thesweeping machine manually quickly enough that the circular broom 10 willrotate at a higher rotational speed than that determined by the electricmotor 25.

[0022] The two overriding couplings 22, 27 are preferably designed asfree-wheeling rollers, as mentioned above. However, other designs ofoverriding couplings can also be used, e.g., ratchet couplings orfriction couplings or the like.

[0023] Instead of the overriding coupling 27, which automaticallyinterrupts the connection when the circular broom 10 is running fasterthan the worm gear wheel 23, other means may also be provided forinterrupting this connection. For example, it is possible to arrangeand/or design the electric motor 25 so that the worm gear wheel 24 isengaged with the gear wheel 23 only when there is an electric powersupply or the power is turned on. As soon as the power supply stops orfails, the connection between the circular broom 10 and the electricmotor 25 is interrupted so the electric motor 25 need not be draggedalong. In a modified embodiment, instead of the overriding coupling 27,a device is provided which cancels the drive connection when thecircular broom 10 is rotating at a faster speed than the gear wheel 23driven by the electric motor 25. It is possible here to make use of thefact that the direction of the force transmitted between the worm gear24 and the gear wheel 23 has changed.

[0024] As mentioned above, in the preferred embodiment, a sweepingroller 30 is connected downstream from the circular broom 10 and ispreferably driven in such a way that it sweeps the bottom in thedirection of travel, i.e., in the opposite direction from a wheelrotating on the floor. The sweeping roller 30 is driven by one or bothof the wheels 31, 32 with which the central or rear area of the sweepingmachine sits on the floor. The sweeping roller 30 has a shaft 34 whichis-equipped with bristles 33 which are mounted in a housing of thesweeping machine. In the simplest embodiment, the sweeping roller 30 isdriven by only one of the two wheels, e.g., the wheel 31. The wheel 31is provided with a gear wheel 35 which meshes with a gear wheel 36 in arotationally fixed mount on the shaft 34. To achieve the result that thesweeping roller 30 is driven in a direction opposite the usual sweepingdirection when the sweeping machine is moved or pulled in the reversedirection, a free-wheeling-coupling 37 is provided between the gearwheel 35 and the wheel 31. When the sweeping machine is moved inreverse, the sweeping roller 30 thus remains standing or rotates furtherslightly due to its inertia.

[0025] In the exemplary embodiment according to FIG. 2, the sweepingroller 30 is driven by an electric motor 38 which drives a gear wheel 39that engages with the gear wheel 36 of the shaft 34 of the sweepingroller 30. The sweeping roller 30 is thus rotating even when thesweeping machine is stopped, i.e., the wheel 31 is not rotating. In thiscase, the free-wheeling coupling 37 interrupts the connection betweenthe wheel and the motor 38 so that the motor 38 does not act as atraversing drive, i.e., it does not drive the wheel 31.

[0026] If the electric motor 38 fails, i.e., because the battery is tooweak or there is no electric power or because of a defect, the sweepingroller 30 is driven by the wheel 31 in the forward direction in onemethod. In order not to have to drag the motor 38 in this situation, afree-wheeling coupling 40 is provided between the electric motor 38 andits gear wheel 39 in this exemplary embodiment. However, thisfree-wheeling coupling can be omitted if the electric motor 38 does notpresent any great resistance to turning and in particular if it does nothave any self-locking gear stage. If in addition it is necessary toensure that the sweeping roller will be driven in the same desireddirection of rotation even if the sweeping machine is being pulled ordriven backwards, even if the electric motor 38 is not functioning, thenaccording to the exemplary embodiment depicted here, another drive isprovided for the sweeping roller 30 and is derived from the opposingwheel 32. This wheel 32 is connected to a gear wheel 41 which meshes viaan intermediate wheel 42 with a gear wheel 43 which is in a rotationallyfixed mount on the shaft 34 of the sweeping roller 30. Depending on thedirection of movement of the sweeping machine, the wheel 31 or the wheel32 then drives the sweeping roller 30 in such a way that it alwaysrotates in the same direction of rotation, regardless of the directionof travel. To ensure that the electric motor 38 does not act on thewheel 32, another overriding coupling 44 is provided between the wheel32 and its gear wheel 41. The overriding couplings 37, 40, 44 arepreferably designed as free-wheeling rollers, but other designs may alsobe provided. For example, ratchet couplings or friction couplings mayalso be used.

[0027] In the simplest embodiment, namely when the sweeping roller 30 isnot driven when the sweeping machine is pulled backward in the event offailure of the electric motor 38 and in which the motor is dragged alongwhen the sweeping machine is moved forward when the electric motor 38has failed, it is sufficient to have an overriding coupling, namely theoverriding coupling 37 between the wheel 31 and its gear wheel 35. Ifthe electric motor 38 is not to be dragged in the event of a motorfailure, the second overriding coupling 40 is necessary, and is arrangedbetween the electric motor 38 and its gear wheel 39. If another positivedrive for the sweeping roller 30 in the previous direction is to beprovided in addition in the event of failure of the electric motor 38and a reverse movement of the sweeping machine, then the second wheel 32must be incorporated into the overall drive system in the mannerdescribed here. In this case a third free-wheeling coupling 44 isnecessary, although it may also be situated between gear wheel 43 andthe shaft 34 of the circular broom 30.

[0028] The foregoing disclosure has been set forth merely to illustratethe invention and is not intended to be limiting. For example, althoughelectric motor drives are mentioned above in the exemplary embodiments,this invention is not limited to the use of electric motors. Instead,any type of motor may be used, in particular internal combustionengines. Since modifications of the disclosed embodiments incorporatingthe spirit and substance of the invention may occur to persons skilledin the art, the invention should be construed to include everythingwithin the scope of the appended claims and equivalents thereof.

What is claimed is:
 1. Hand-operated sweeping machine having twocircular brooms that are mounted in a front area of the sweeping machineand can be driven to rotate in opposite directions with a motor drive,wherein, in addition to the motor drive for the circular brooms, thereis also provided driving means to transfer driving forces derived fromforward motion of the sweeping machine to the circular brooms and meansfor automatically interrupting a connection between the motor drive andthe driving means.
 2. Sweeping machine as claimed in claim 1, wherein aseparate motor drive and separate driving means are provided for eachcircular broom.
 3. Sweeping machine as claimed in claim 1 wherein anoverriding coupling which allows the circular brooms to run ahead of thedriving means is situated between the driving means which transmit thedriving forces derived from the forward motion, and the circular brooms.4. Sweeping machine as claimed in claim 2 wherein an overriding couplingwhich allows the circular broom to run ahead of the driving means issituated between the driving means which transmit the driving forcesderived from the forward motion, and the circular broom.
 5. Sweepingmachine as claimed in claim 1, wherein an overriding coupling whichallows the circular brooms to run ahead is situated between the circularbrooms and the motor drive.
 6. Sweeping machine as claimed in claim 2,wherein an overriding coupling which allows the circular broom to runahead is situated between the circular broom and its motor drive. 7.Sweeping machine as claimed in claim 3, wherein an overriding couplingwhich allows the circular broom to run ahead is situated between thecircular broom and its motor drive.
 8. Sweeping machine as claimed inclaim 3, wherein at least one overriding coupling is designed as afree-wheeling coupling.
 9. Sweeping machine as claimed in claim 4,wherein at least one overriding coupling is designed as a free-wheelingcoupling.
 10. Sweeping machine as claimed in claim 5, wherein at leastone overriding coupling is designed as a free-wheeling coupling. 11.Sweeping machine as claimed in claim 6, wherein at least one overridingcoupling is designed as a free-wheeling coupling.
 12. Sweeping machineas claimed in claim 7, wherein at least one overriding coupling isdesigned as a free-wheeling coupling.
 13. Sweeping machine as claimed inclaim 1, wherein the means for interrupting a drive connection betweenthe circular brooms and the motor drive includes at least one separationelement which responds when the circular broom is turning more rapidlythan the motor drive.
 14. Sweeping machine as claimed in claim 2,wherein the means for interrupting a drive connection between one of thecircular brooms and its respective motor drive includes at least oneseparation element which responds when the circular broom is turningmore rapidly than the motor drive.
 15. Sweeping machine as claimed inclaim 1, wherein the motor drive is an electric motor drive, and themeans for interrupting a drive connection between the circular broomsand the electric motor drive includes at least one separation elementwhich is held electrically in an engaged position.
 16. Sweeping machineas claimed in claim 2, wherein the means for interrupting a driveconnection between at least one of the circular brooms and itsrespective electric motor drive includes at least one separation elementwhich is held electrically in an engaged position.
 17. Sweeping machineas claimed in claim 1, wherein a sweeping roller which is aligned acrossthe direction of travel is provided with a motor drive and with drivingmeans with which driving forces derived from the forward motion of thesweeping machine can be transferred to the sweeping roller, and meansfor automatic interruption of a drive connection between the rollerdriving means and the motor drive of the sweeping roller are provided.18. Sweeping machine as claimed in claim 17, wherein an overridingcoupling is provided between the roller driving means and the motordrive of the sweeping roller.
 19. Sweeping machine as claimed in claim17, wherein the means for interruption are held electrically in anengaged position.
 20. A hand-operated sweeping machine, comprising: twocircular brooms mounted in a front area of the sweeping machine; acircular broom motor drive; a driving mechanism; and an interruptingmechanism, wherein: the motor drive rotates the circular brooms inopposite directions, the driving mechanism transfers driving forcesderived from forward motion of the sweeping machine to the circularbrooms, and the interrupting mechanism automatically prevents the motordrive from driving the driving mechanism.
 21. A method for operating ahand-operated sweeping machine having two circular brooms mounted in afront area of the sweeping machine, a circular broom motor drive, adriving mechanism which transfers driving forces derived from forwardmotion of the sweeping machine to the circular brooms, and aninterrupting mechanism, comprising the steps of: rotating the circularbrooms in opposite directions with the one of the motor drive and thedriving mechanism that can drive the circular brooms faster; andinterrupting automatically with the interrupting mechanism a connectionbetween the motor drive and the driving mechanism to prevent the motordrive from driving the driving mechanism.